''Ultrapithecus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus of oldfieldthomasiid notoungulate that lived during the Middle Eocene of what is now Argentina.

Description

This genus is mostly known from its dentition, and a detailed reconstruction is impossible. It can be supposed that ''Ultrapithecus'' was, like its better known relatives, similar in size and appearance with a modern marmot. Its dentition consisted of low-crowned (brachydont) teeth. The molars were devoid of mesostyle, while the premolars lacked the fold of the metacone.

Classification

The genus ''Ultrapithecus'' was first described in 1901 by Florentino Ameghino, based on fossil remains found in

Argentine Argentines (mistakenly translated Argentineans in the past; in Spanish (masculine) or (feminine)) are people identified with the country of Argentina. This connection may be residential, legal, historical or cultural. For most Argentines, s ...

terrains dated from the end of the Middle Eocene. Ameghino described two species, ''Ultrapithecus rutilans'' and ''U. rusticulus'', and thought that this genus was an archaic primate, hence its genus name, ''Ultrapithecus'', meaning "monkey from the other side", referring to its discovery in South America instead of the

Old World The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia, which were previously thought of by the ...

. ''Ultrapithecus'' was subsequently placed within the order Notoungulata, and the two species are considered synonyms, with ''U. rutilans'' taking precedence. ''Ultrapithecus'' has historically been placed with the family

Oldfieldthomasiidae Oldfieldthomasiidae is an extinct family of notoungulate mammals known from the Late Paleocene to Late Eocene of South America. The family was classified by George Gaylord Simpson in 1945 and a synonym is Acoelodidae, defined by Florentino Ameghi ...

,G. G. Simpson. 1967. The beginning of the age of mammals in South America. Part II. Bulletin of the American Museum of Natural History 137:1-260 but more recent studies tends to indicate that this family was paraphyletic, with ''Ultrapithecus'' being a member of an Eocene adaptive radiation of archaic notoungulates, nested at the basis of the suborder

Typotheria Typotheria is a suborder of the extinct mammalian order Notoungulata and includes five families: Archaeopithecidae, Campanorcidae, Interatheriidae, Mesotheriidae, and Oldfieldthomasiidae. CifelliCifelli, Richard L. 1993. The phylogeny of the nat ...

.*G. Billet. 2011. Phylogeny of the Notoungulata (Mammalia) based on cranial and dental characters. Journal of Systematic Palaeontology. 9 (4): 481–97. doi:10.1080/14772019.2010.528456. OCLC 740994816. It seems to have been closely related with the genus '' Kibenikhoria''.

References

*F. Ameghino. 1901. Notices préliminaires sur des ongulés nouveaux des terrains crétacés de Patagonie reliminary notes on new ungulates from the Cretaceous terrains of Patagonia Boletin de la Academia Nacional de Ciencias de Córdoba 16:349-429 *G. G. Simpson. 1967. The beginning of the age of mammals in South America. Part II. Bulletin of the American Museum of Natural History 137:1-260 *R. Cifelli. 1985. Biostratigraphy of the Casamayoran, Early Eocene of Patagonia. American Museum Novitates 2820:1-26 Typotheres Eocene mammals of South America Paleogene Argentina Fossils of Argentina Taxa named by Florentino Ameghino Fossil taxa described in 1901 Prehistoric placental genera Golfo San Jorge Basin Sarmiento Formation {{Mammal-stub